Added Codabar-Reader; Missing fixtures; Error for stdlib must be fixed
Christoph Oberhofer
10 years ago
parent
e642ac15cb
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/* jshint undef: true, unused: true, browser:true, devel: true */
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/* global define */
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define(
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[
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"./barcode_reader"
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],
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function(BarcodeReader) {
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"use strict";
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function CodabarReader() {
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BarcodeReader.call(this);
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this._counters = [];
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}
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var properties = {
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ALPHABETH_STRING: {value: "0123456789-$:/.+ABCD"},
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ALPHABET: {value: [48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 45, 36, 58, 47, 46, 43, 65, 66, 67, 68]},
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CHARACTER_ENCODINGS: {value: [0x003, 0x006, 0x009, 0x060, 0x012, 0x042, 0x021, 0x024, 0x030, 0x048, 0x00c, 0x018, 0x045, 0x051, 0x054, 0x015, 0x01A, 0x029, 0x00B, 0x00E]},
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START_END: {value: [0x01A, 0x029, 0x00B, 0x00E]},
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MIN_ENCODED_CHARS: {value: 4},
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MAX_ACCEPTABLE: {value: 2.0},
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PADDING: {value: 1.5}
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};
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CodabarReader.prototype = Object.create(BarcodeReader.prototype, properties);
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CodabarReader.prototype.constructor = CodabarReader;
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CodabarReader.prototype._decode = function() {
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var self = this,
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result = [],
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start,
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decodedChar,
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pattern,
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nextStart,
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end;
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self._fillCounters();
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start = self._findStart();
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if (!start) {
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return null;
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}
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nextStart = start.startCounter;
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do {
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pattern = self._toPattern(nextStart);
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if (pattern < 0) {
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return null;
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}
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decodedChar = self._patternToChar(pattern);
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if (decodedChar < 0){
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return null;
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}
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result.push(decodedChar);
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nextStart += 8;
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if (result.length > 1 && self._isStartEnd(pattern)) {
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break;
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}
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} while(nextStart < self._counters.length);
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// verify end
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if ((result.length - 2) < self.MIN_ENCODED_CHARS || !self._isStartEnd(pattern)) {
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return null;
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}
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// verify end white space
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if (!self._verifyWhitespace(start.startCounter, nextStart - 8)){
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return null;
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}
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if (!self._validateResult(result, start.startCounter)){
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return null;
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}
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nextStart = nextStart > self._counters.length ? self._counters.length : nextStart;
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end = start.start + self._sumCounters(start.startCounter, nextStart - 8);
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return {
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code : result.join(""),
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start : start.start,
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end : end,
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startInfo : start,
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decodedCodes : result
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};
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};
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CodabarReader.prototype._verifyWhitespace = function(startCounter, endCounter) {
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if ((startCounter - 1 <= 0) || this._counters[startCounter-1] >= (this._calculatePatternLength(startCounter) / 2.0)) {
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if ((endCounter + 8 >= this._counters.length) || this._counters[endCounter+7] >= (this._calculatePatternLength(endCounter) / 2.0)) {
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return true;
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}
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}
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return false;
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};
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CodabarReader.prototype._calculatePatternLength = function(offset) {
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var i,
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sum = 0;
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for (i = offset; i < offset + 7; i++) {
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sum += this._counters[i];
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}
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return sum;
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};
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CodabarReader.prototype._thresholdResultPattern = function(result, startCounter){
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var self = this,
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categorization = {
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space: {
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narrow: { size: 0, counts: 0, min: 0, max: Number.MAX_VALUE},
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wide: {size: 0, counts: 0, min: 0, max: Number.MAX_VALUE}
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},
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bar: {
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narrow: { size: 0, counts: 0, min: 0, max: Number.MAX_VALUE},
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wide: { size: 0, counts: 0, min: 0, max: Number.MAX_VALUE}
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}
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},
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kind,
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cat,
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i,
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j,
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pos = startCounter,
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pattern;
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for (i = 0; i < result.length; i++){
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pattern = self._charToPattern(result[i]);
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for (j = 6; j >= 0; j--) {
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kind = (j & 1) === 2 ? categorization.bar : categorization.space;
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cat = (pattern & 1) === 1 ? kind.wide : kind.narrow;
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cat.size += self._counters[pos + j];
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cat.counts++;
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pattern >>= 1;
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}
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pos += 8;
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}
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["space", "bar"].forEach(function(key) {
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var kind = categorization[key];
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kind.wide.min = (kind.narrow.size/kind.narrow.counts + kind.wide.size / kind.wide.counts) / 2;
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kind.narrow.max = kind.wide.min;
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kind.wide.max = (kind.wide.size * self.MAX_ACCEPTABLE + self.PADDING) / kind.wide.counts;
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});
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return categorization;
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};
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CodabarReader.prototype._charToPattern = function(char) {
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var self = this,
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charCode = char.charCodeAt(0),
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i;
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for (i = 0; i < self.ALPHABET.length; i++) {
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if (self.ALPHABET[i] === charCode){
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return self.CHARACTER_ENCODINGS[i];
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}
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}
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return 0x0;
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};
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CodabarReader.prototype._validateResult = function(result, startCounter) {
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var self = this,
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thresholds = self._thresholdResultPattern(result, startCounter),
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i,
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j,
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kind,
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cat,
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size,
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pos = startCounter,
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pattern;
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for (i = 0; i < result.length; i++) {
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pattern = self._charToPattern(result[i]);
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for (j = 6; j >= 0; j--) {
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kind = (j & 1) === 0 ? thresholds.bar : thresholds.space;
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cat = (pattern & 1) === 1 ? kind.wide : kind.narrow;
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size = self._counters[pos + j];
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if (size < cat.min || size > cat.max) {
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return false;
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}
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pattern >>= 1;
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}
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pos += 8;
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}
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return true;
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};
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CodabarReader.prototype._fillCounters = function() {
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var self = this,
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counterPos = 0,
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isWhite = true,
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offset = self._nextUnset(self._row),
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i;
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self._counters.length = 0;
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self._counters[counterPos] = 0;
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for (i = offset; i < self._row.length; i++) {
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if (self._row[i] ^ isWhite) {
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this._counters[counterPos]++;
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} else {
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counterPos++;
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this._counters[counterPos] = 1;
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isWhite = !isWhite;
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}
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}
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};
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CodabarReader.prototype._patternToChar = function(pattern) {
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var i,
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self = this;
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for (i = 0; i < self.CHARACTER_ENCODINGS.length; i++) {
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if (self.CHARACTER_ENCODINGS[i] === pattern) {
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return String.fromCharCode(self.ALPHABET[i]);
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}
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}
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return -1;
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};
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CodabarReader.prototype._computeAlternatingThreshold = function(offset, end) {
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var i,
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min = Number.MAX_VALUE,
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max = 0,
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counter;
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for (i = offset; i < end; i += 2){
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counter = this._counters[i];
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if (counter > max) {
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max = counter;
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}
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if (counter < min) {
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min = counter;
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}
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}
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return ((min + max) / 2.0) | 0;
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};
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CodabarReader.prototype._toPattern = function(offset) {
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var numCounters = 7,
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end = offset + numCounters,
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barThreshold,
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spaceThreshold,
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bitmask = 1 << (numCounters - 1),
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pattern = 0,
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i,
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threshold;
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if (end > this._counters.length) {
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return -1;
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}
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barThreshold = this._computeAlternatingThreshold(offset, end);
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spaceThreshold = this._computeAlternatingThreshold(offset + 1, end);
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for (i = 0; i < numCounters; i++){
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threshold = (i & 1) === 0 ? barThreshold : spaceThreshold;
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if (this._counters[offset + i] > threshold) {
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pattern |= bitmask;
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}
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bitmask >>= 1;
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}
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return pattern;
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};
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CodabarReader.prototype._isStartEnd = function(pattern) {
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var i;
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for (i = 0; i < this.START_END.length; i++) {
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if (this.START_END[i] === pattern) {
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return true;
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}
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}
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return false;
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};
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CodabarReader.prototype._sumCounters = function(start, end) {
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var i,
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sum = 0;
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for (i = start; i < end; i++) {
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sum += this._counters[i];
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}
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return sum;
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};
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CodabarReader.prototype._findStart = function() {
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var self = this,
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i,
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pattern,
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start = self._nextUnset(self._row),
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end;
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for (i = 1; i < this._counters.length; i++) {
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pattern = self._toPattern(i);
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if (pattern !== -1 && self._isStartEnd(pattern)) {
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// TODO: Look for whitespace ahead
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start += self._sumCounters(0, i);
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end = start + self._sumCounters(i, i + 8);
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return {
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start: start,
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end: end,
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startCounter: i,
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endCounter: i + 8
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};
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}
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}
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};
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return (CodabarReader);
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}
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);
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